Network Working Group                                         R. Stewart
Internet-Draft                                       Cisco Systems, Inc.
Expires: April 22, 2004                                           Q. Xie
                                                          Motorola, Inc.
                                                             M. Stillman
                                                                   Nokia
                                                               M. Tuexen
                                                        October 23, 2003


  Aggregate Server Access Protocol (ASAP) and Endpoint Name Resolution
                       Protocol (ENRP) Parameters
                draft-ietf-rserpool-common-param-05.txt

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that other
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at http://
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   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on April 22, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   This document details the parameters of the Aggregate Server Access
   Protocol (ASAP) and Endpoint Name Resolution Protocol (ENRP)
   protocols defined within the Reliable Server Pooling (RSERPOOL)
   architecture.






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Table of Contents

   1.     Introduction . . . . . . . . . . . . . . . . . . . . . . .   3
   1.1    Conventions  . . . . . . . . . . . . . . . . . . . . . . .   3
   2.     Parameters in General  . . . . . . . . . . . . . . . . . .   4
   3.     ENRP-ASAP Common Parameters  . . . . . . . . . . . . . . .   5
   3.1    IPv4 Address Parameter . . . . . . . . . . . . . . . . . .   6
   3.2    IPv6 Address Parameter . . . . . . . . . . . . . . . . . .   7
   3.3    SCTP Transport Parameter . . . . . . . . . . . . . . . . .   7
   3.4    TCP Transport Parameter  . . . . . . . . . . . . . . . . .   8
   3.5    UDP Transport Parameter  . . . . . . . . . . . . . . . . .   9
   3.6    Pool Member Selection Policy Parameter . . . . . . . . . .  10
   3.6.1  Round Robin Policy . . . . . . . . . . . . . . . . . . . .  12
   3.6.2  Least Used Policy  . . . . . . . . . . . . . . . . . . . .  12
   3.6.3  Least Used with Degradation Policy . . . . . . . . . . . .  12
   3.6.4  Weighted Round Robin Policy  . . . . . . . . . . . . . . .  13
   3.7    Pool Handle Parameter  . . . . . . . . . . . . . . . . . .  13
   3.8    Pool Element Parameter . . . . . . . . . . . . . . . . . .  13
   3.9    Server Information Parameter . . . . . . . . . . . . . . .  15
   3.10   Operation Error Parameter  . . . . . . . . . . . . . . . .  16
   3.10.1 Unspecified Error  . . . . . . . . . . . . . . . . . . . .  17
   3.10.2 Unrecognized Parameter Error . . . . . . . . . . . . . . .  17
   3.10.3 Unrecognized Message Error . . . . . . . . . . . . . . . .  17
   3.10.4 Invalid Values Error . . . . . . . . . . . . . . . . . . .  17
   3.10.5 Non-unique PE Identifier Error . . . . . . . . . . . . . .  18
   3.10.6 Inconsistent Pool Policy Error . . . . . . . . . . . . . .  18
   3.10.7 Lack of Resources Error  . . . . . . . . . . . . . . . . .  18
   3.10.8 Inconsistent Transport Type Error  . . . . . . . . . . . .  18
   3.10.9 Inconsistent Data/Control Configuration Error  . . . . . .  18
   3.11   Cookie Parameter . . . . . . . . . . . . . . . . . . . . .  18
   3.12   PE Identifier Parameter  . . . . . . . . . . . . . . . . .  19
   3.13   PE Checksum Parameter  . . . . . . . . . . . . . . . . . .  19
   4.     Common Message Formats . . . . . . . . . . . . . . . . . .  21
   5.     Security Considerations  . . . . . . . . . . . . . . . . .  23
          Normative References . . . . . . . . . . . . . . . . . . .  24
          Authors' Addresses . . . . . . . . . . . . . . . . . . . .  24
          Intellectual Property and Copyright Statements . . . . . .  26














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1. Introduction

   Aggregate Server Access Protocol (ASAP) [3] in conjunction with the
   Endpoint Name Resolution Protocol (ENRP) [4] provides a high
   availability data transfer mechanism over IP networks.

   Both protocols work together and so share many common parameters used
   in message formats. This document details the common message
   parameters shared between the two protocols. This document provides
   parameter formats only, for procedures and message composition please
   refer to the respective ASAP [3] and ENRP [4] documents.

1.1 Conventions

   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
   SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when
   they appear in this document, are to be interpreted as described in
   RFC2119 [2].

































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2. Parameters in General

   All parameters described below MUST be in Network Byte Order (a.k.a.
   Big Endian, i.e., the most significant byte first) during
   transmission.

   Please note that messages in both ENRP and ASAP are often composed of
   multiple parameters. These parameters may also be nested. In such a
   case a nested parameter will include the length of the padding
   between the nested parameters but not the last padding.









































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3. ENRP-ASAP Common Parameters

   Parameters are defined in the following Type-Length-Value (TLV)
   format:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Parameter Type       |       Parameter Length        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                                                               :
      :                       Parameter Value                         :
      :                                                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Parameter Type:  16 bits (unsigned integer)

   The Type field is a 16 bit identifier of the type of parameter. It
   takes a value of 0 to 65534.

   The value of 65535 is reserved for IETF-defined extensions. Values
   other than those defined in specific ENRP parameter description are
   reserved by IETF. (Additional types, when needed, will be defined in
   the future through appropriate IETF/IANA procedures.)

   The Parameter Types are encoded such that the highest-order two bits
   specify the action that must be taken if the processing endpoint does
   not recognize the Parameter Type.

   00 Stop processing this ENRP or ASAP message and discard it, do not
      process any further parameters within it.

   01 Stop processing this ENRP or ASAP message and discard it, do not
      process any further parameters within it, and report the
      unrecognized parameter in an 'Unrecognized Parameter' error (see
      Section 3.10).

   10 Skip this parameter and continue processing.

   11 Skip this parameter and continue processing, but report the
      unrecognized parameter in an 'Unrecognized Parameter' error (see
      Section 3.10).

   The values of parameter types are defined as follows:







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      Value     Parameter Type
      -----     ----------
      0x0       - (reserved by IETF)
      0x1       - IPv4 Address
      0x2       - IPv6 Address
      0x3       - SCTP Transport
      0x4       - TCP Transport
      0x5       - UDP Transport
      0x6       - Pool Member Selection Policy
      0x7       - Pool Handle
      0x8       - Pool Element
      0x9       - Server Information
      0xa       - Operation Error
      0xb       - Cookie
      0xc       - PE Identifier

      others    - (reserved by IETF)

   Parameter Length:  16 bits (unsigned integer)

   The Parameter Length field contains the size of the parameter in
   bytes, including the Parameter Type, Parameter Length, and Parameter
   Value fields.  Thus, a parameter with a zero-length Parameter Value
   field would have a Length field of 4.

   The total length of a parameter (including Type, Parameter Length and
   Value fields) MUST be a multiple of 4 bytes.  If the length of the
   parameter is not a multiple of 4 bytes, the sender MUST pad the
   parameter at the end (i.e., after the Parameter Value field) with all
   zero bytes.  The length of this padding is not included in the
   Parameter Length field.  A sender MUST NOT pad with more than 3
   bytes.  The receiver MUST ignore the padding bytes.

   (Editor's note: clarify further that any padding inside in the
   parameter, such as the padding in sub-param is included in the total
   length)

   Parameter Value: variable-length.

   The Parameter Value field contains the actual information to be
   transferred in the parameter.

3.1 IPv4 Address Parameter

   This parameter defines a TLV that carries an IPv4 address.






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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 0x1             |      Length = 0x8             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        IPv4 Address                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   IPv4 Address: 32 bits (unsigned integer)

   Contains an IPv4 address. It is binary encoded.

3.2 IPv6 Address Parameter

   This parameter defines a TLV that carries an IPv6 address.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Type = 0x2         |          Length = 0x14        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                         IPv6 Address                          |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   IPv6 Address: 128 bit (unsigned integer)

   Contains an IPv6 address. It is binary encoded.

3.3 SCTP Transport Parameter

   This parameter defines a TLV that describes a user transport using
   SCTP protocol.
















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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 0x3             |      Length = variable        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        SCTP port              |          Transport Use        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                     IPv4 or IPv6 Address #1                   :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                               :
   :                              ...                              :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                     IPv4 or IPv6 Address #n                   :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets,
   including the Type, Length, SCTP port, reserved fields, and all IP
   address parameters present.

   SCTP port: 16 bits (unsigned integer)

   The SCTP port number signed to this SCTP user transport.

   Transport use: 16 bits (unsigned integer)

   This field represents how the pool element intends this transport
   address to be used. The field MUST be populated with one of the
   following values:


   Type              |    Value
   ------------------+----------------
   DATA ONLY         |   0x0000
   DATA plus CONTROL |   0x0001


   IPv4 or IPv6 Address #1 - #n:

   Each indicates an IPv4 or IPv6 address parameter (as defined above in
   Section 3.1 and Section 3.2) assigned to this SCTP user transport. An
   SCTP Transport parameter may have a mixed list of IPv4 and IPv6
   addresses and at least one IP address parameter MUST be present in an
   SCTP transport parameter.

3.4 TCP Transport Parameter




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   This parameter defines a TLV that describes a user transport using
   TCP protocol.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 0x4             |      Length = variable        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         TCP port              |          Transport Use        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                     IPv4 or IPv6 Address                      :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets,
   including the Type, Length, TCP port, reserved fields, and IP address
   parameter.

   TCP port: 16 bits (unsigned integer)

   The TCP port number signed to this TCP user transport.

   Transport use: 16 bits (unsigned integer)

   This field represents how the pool element intends this transport
   address to be used. The field MUST be populated with one of the
   following values:

   Type              |    Value
   ------------------+----------------
   DATA ONLY         |   0x0000
   DATA plus CONTROL |   0x0001


   IPv4 or IPv6 Address:

   Indicates an IPv4 or IPv6 address parameter (as defined above in
   Section 3.1 and Section 3.2) assigned to this TCP user transport.
   Unlike in an SCTP transport, only one IP address parameter can be
   present in a TCP transport parameter.

3.5 UDP Transport Parameter

   This parameter defines a TLV that describes a user transport using
   UDP protocol.





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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 0x5             |      Length = variable        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         UDP port              |          (reserved)           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                     IPv4 or IPv6 Address                      :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets,
   including the Type, Length, UDP port, reserved fields, and IP address
   parameter.

   UDP port: 16 bits (unsigned integer)

   The UDP port number signed to this UDP user transport.

   IPv4 or IPv6 Address:

   Indicates an IPv4 or IPv6 address parameter (as defined above in
   Section 3.1 and Section 3.2) assigned to this UDP user transport.
   Unlike in an SCTP transport, only one IP address parameter can be
   present in a UDP transport parameter.

   Note: A UDP port MUST NOT be used for control information. For this
   reason, no Transport Use field is provided. UDP MUST always be
   treated as a "Data Only" type transport use.

3.6 Pool Member Selection Policy Parameter

   This parameter defines a pool member selection policy. RSERPOOL
   supports multiple pool member selection policies and also allows
   definition of new selection policies in the future.

   The enforcement rules and handling procedures of all the policies are
   defined in Section xxxxx in ASAP [3].

   All pool member selection policies, both present and future, MUST use
   the following general parameter format:









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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 0x6             |      Length = variable        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Policy Type   |     Policy-specific Data....
   +-+-+-+-+-+-+-+-+------------------------------------------------

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets,
   including the Type, Length, Policy Type, and the Policy-specific Data
   fields.

   Note, the Length field value will NOT include any padding at the end
   of the parameter.

   Policy Type: 8 bits (unsigned integer)

   Specifies the type of selection policy.

   Currently defined policy types are:

     Value     Policy
     -----     ---------
     0x0       (reserved by IETF)
     0x1       Round Robin
     0x2       Least Used
     0x3       Least Used with Degradation (a.k.a. dog pile)
     0x4       Weighted Round Robin
     others    (reserved by IETF)

   Policy-specific Data:

   The structure and fields for each presently defined policy types are
   described in detail in the following subsections. The enforcement
   rules and handling procedures of these policies are defined in
   Section xxxxx in ASAP [3].













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3.6.1 Round Robin Policy

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Param Type = 0x6           |      Length = 0x8             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Policy=0x1   |                (reserved)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------------------------+

   Reserved: 24 bits

   MUST be set to 0's by sender and ignored by the receiver.

3.6.2 Least Used Policy

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Param Type = 0x6           |      Length = 0x8             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Policy=0x2   |                 Load                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------------------------+

   Load: 24 bits (signed integer)

   (TBD)

3.6.3 Least Used with Degradation Policy

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Param Type = 0x6           |      Length = 0x8             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Policy=0x3   |                 Load                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------------------------+

   Load: 24 bits (signed integer)

   (TBD)










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3.6.4 Weighted Round Robin Policy

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Param Type = 0x6           |      Length = 0x8             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Policy=0x4   |                 Weight                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------------------------+

   Load: 24 bits (signed integer)

   (TBD)

3.7 Pool Handle Parameter

   This parameter holds a pool handle (i.e., a pool name).

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Type = 0x7            |       Length=variable         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                               :
   :                          Pool Handle                          :
   :                                                               :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets,
   including the Type, Length, and Pool Handle string.

   Note, the value in Length field will NOT cover any padding at the end
   of the parameter.

   Pool Handle:

   defined as a sequence of (Length - 4) bytes.

3.8 Pool Element Parameter

   This parameter is used in multiple ENRP messages to represent an ASAP
   endpoint (i.e., a PE in a pool) and the associated information, such
   as its transport address, selection policy, and other operational or
   status information of the PE.





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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Type = 0x8            |       Length=variable         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         PE Identifier                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Home ENRP Server Identifier                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Registration Life                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                      User Transport param                     :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                 Member Selection Policy param                 :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets,
   including the Type, Length, PE Identifier, Registration Life, User
   Transport, and Member Selection Policy parameters.

   Note, the value in Length field will NOT cover any padding at the end
   of this Pool Element parameter.

   PE Identifier: 32 bits (unsigned integer)

   Uniquely identifies the PE in the pool. The PE picks its identifier
   when it starts up. See Section ???? in [ASAP] for recommendations on
   PE identifier generation.

   Home ENRP Server Identifier: 32 bits (unsigned integer)

   Indicates the current home ENRP server of this PE. Set to all 0's if
   the PE's home ENRP server is undetermined.

   Registration Life: 32 bits (signed integer)

   Indicates the life time of the registration in number of seconds. A
   value of -1 indicates infinite life time.

   User Transport:

   This can be either an SCTP, TCP, or UDP type transport parameter (see
   Section 3.3, Section 3.4, Section 3.5). A PE MUST have one and only
   one User Transport.

   Member Selection Policy:



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   Contains one of the defined member selection policy parameters (see
   Section 3.6).

3.9 Server Information Parameter

   This parameter is used in ENRP to pass basic information of an ENRP
   server.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Type = 0x9            |       Length=variable         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Server ID                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|                        (reserved)                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                       Server Transport                        :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets.

   Note, the value in Length field will NOT cover any padding at the end
   of the parameter.

   Server ID: 32 bit (unsigned integer)

   This is the ID of the ENRP server, as defined in Section xxxxxx in
   ENRP [4] .

   Multicast Flag (M): 1 bit

   If set to '1', indicates the ENRP server is allowed to use multicast
   for communications. If set to '0', multicast is not used by the
   server.

   Reserved: 31 bits

   MUST be set to 0's by sender and ignored by the receiver.

   Server Transport:

   This is an SCTP Transport Parameter, as defined in Section 3.3 that
   contains the network access address(es), SCTP port number, etc. of
   the ENRP server.




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3.10 Operation Error Parameter

   This parameter is used in both ENPR and ASAP for a message sender to
   report an error(s) to a message receiver.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Type = 0xa           |       Length=variable         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                               :
   :                    one or more Error Causes                   :
   :                                                               :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of octets.

   Note, the value in Length field will NOT cover any padding at the end
   of the parameter.

   Error causes are defined as variable-length parameters using the
   following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Cause Code          |       Cause Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                               :
   :                    Cause-specific Information                 :
   :                                                               :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Cause Code: 16 bits (unsigned integer)

   Defines the type of error condition being reported.













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         Cause Code
         Value           Cause Code
         ---------      ----------------
          0              Unspecified Error
          1              Unrecognized Parameter
          2              Unrecognized Message
          3              Invalid Values
          4              Non-unique PE Identifier
          5              Inconsistent Pooling Policy
          6              Lack of Resources
          7              Inconsistent Transport Type
          8           Inconsistent Data/Control Configuration
         other values    reserved by IETF

   Cause Length: 16 bits (unsigned integer)

   Set to the size of the parameter in bytes, including the Cause Code,
   Cause Length, and Cause-Specific Information fields, but not
   including any padding at the end of this error cause TLV.

   Cause-specific Information: variable length

   This field carries the details of the error condition.

   The following subsections (Section 3.10.1 - Section 3.10.9) define
   specific error causes.

3.10.1 Unspecified Error

   This error cause is used to report an unspecified error by the
   sender. There is no cause specific information.

3.10.2 Unrecognized Parameter Error

   This error cause is used to report an unrecognized parameter. The
   unrecognized parameter TLV is included as cause specific information.

3.10.3 Unrecognized Message Error

   This error cause is used to report an unrecognized message. The
   unrecognized message TLV is included as cause specific information.

3.10.4 Invalid Values Error

   This error cause is used to report one or more invalid values found
   in a received parameter. The offending TLV that contains the invalid
   value(s) is included as cause specific information.




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3.10.5 Non-unique PE Identifier Error

   This error cause is used by an ENRP server to indicate to a
   registering PE that the PE Identifier it chooses has already been
   used by another PE in the pool. There is no cause specific
   information.

3.10.6 Inconsistent Pool Policy Error

   This error cause is used by an ENRP server to indicate to a
   registering PE that the Pool Policy it chooses does not match the
   overall policy of the pool. A Pool Member Selection Policy TLV (see
   Section 3.6) that indicates the overall pool policy is included as
   cause specific information.

3.10.7 Lack of Resources Error

   This error cause is used to indicate that the sender does not have
   certain resources to perform a requested function. There is no cause
   specific information.

3.10.8 Inconsistent Transport Type Error

   This error cause is used by an ENRP server to indicate to a
   registering PE that the User Transport it chooses does not match the
   overall user transport of the pool. A Transport TLV that indicates
   the overall pool user transport type is included as cause specific
   information.

3.10.9 Inconsistent Data/Control Configuration Error

   This error cause is used by an ENRP server to indicate to a
   registering PE that the Transport Use field in the User Transport it
   sent in its registration is inconsistent to the pool's overall data/
   control channel configuration. There is no cause specific
   information.

3.11 Cookie Parameter

   This parameter defines a TLV that carries a Cookie.











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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Type = 0xb         |       Length=variable         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                               :
   :                             Cookie                            :
   :                                                               :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Length: 16 bits (unsigned integer)

   Indicates the entire length of the parameter in number of bytes,
   including the Type, Length, and Cookie.

   Cookie: variable length

   The Cookie is an arbitrary byte string of (Length - 4) bytes.

3.12 PE Identifier Parameter

   This parameter defines a TLV that carries a PE Identifier.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Type = 0xc         |         Length=0x8            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         PE Identifier                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   PE Identifier: 32 bits (unsigned integer)

   Uniquely identifies the PE in the pool. The PE picks its identifier
   when it starts up. See Section ???? in ASAP [3] for recommendations
   on PE identifier generation.

3.13 PE Checksum Parameter

   This parameter defines a TLV that carries a PE Checksum.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Type = 0xd         |         Length=0x8            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         PE Checksum                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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   PE Checksum: 32 bits (unsigned integer)

   An overall checksum of all PEs in the current namespace owned by an
   ENRP server (which is normally the sender of this TLV). The
   definition and calculation of this checksum is defined in Section
   ???? in ENRP [4].













































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4. Common Message Formats

   The figure below illustrates the common format for all ASAP and ENRP
   messages. Each message is formatted with a Message Type field, a
   message-specific Flag field, a Message Length field, and a Value
   field.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Message Type  |   Msg Flags   |        Message Length         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                               :
   :                        Message Value                          :
   :                                                               :
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Message Type: 8 bits (unsigned integer)

   This field identifies the type of information contained in the
   Message Value field. It takes a value from 0 to 254.  The value of
   255 is reserved for future use as an extension field.

   Message Types are encoded such that the highest-order two bits
   specify the action that must be taken if the message receiver does
   not recognize the Message Type.

   00 Stop processing this message and discard it.

   01 Stop processing this message and discard it, and report the
      unrecognized message in an 'Unrecognized Message' error (see
      Section 3.10.3).

   10 reserved.

   11 reserved.

   Message Flags: 8 bits

   The usage of these bits depends on the message type as given by the
   Message Type. Unless otherwise specified, they are set to zero on
   transmit and are ignored on receipt.

   Message Length: 16 bits (unsigned integer)

   This value represents the size of the message in bytes including the
   Message Type, Message Flags, Message Length, and Message Value
   fields. Therefore, if the Message Value field is zero-length, the



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   Length field will be set to 4.

   Note, the value in Message Length field will NOT cover any padding at
   the end of this message.

   Message Value: variable length

   The Message Value field contains the actual information to be
   transferred in the message.  The usage and format of this field is
   dependent on the Message Type.

   The total length of a message (including Type, Length and Value
   fields) MUST be a multiple of 4 bytes.  If the length of the message
   is not a multiple of 4 bytes, the sender MUST pad the message with
   all zero bytes and this padding is not included in the message length
   field. The sender should never pad with more than 3 bytes.  The
   receiver MUST ignore the padding bytes.


































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5. Security Considerations

   This document contains common parameter formats only. As such it
   specifies no new security constraints on either ENRP or ASAP. Details
   on ENRP and ASAP security constraints are addressed in ENRP [4] and
   ASAP [3] .













































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Normative References

   [1]  Bradner, S., "The Internet Standards Process -- Revision 3", BCP
        9, RFC 2026, October 1996.

   [2]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.

   [3]  Stewart, R., Xie, Q., Stillman, M. and M. Tuexen, "Aggregate
        Server Access Protocol (ASAP)", draft-ietf-rserpool-asap-08
        (work in progress), October 2003.

   [4]  Xie, Q., Stewart, R. and M. Stillman, "Endpoint Name Resolution
        Protocol (ENRP)", draft-ietf-rserpool-enrp-07 (work in
        progress), October 2003.


Authors' Addresses

   Randall R. Stewart
   Cisco Systems, Inc.
   8725 West Higgins Road
   Suite 300
   Chicago, IL  60631
   USA

   Phone: +1-815-477-2127
   EMail: rrs@cisco.com


   Qiaobing Xie
   Motorola, Inc.
   1501 W. Shure Drive, #2309
   Arlington Heights, IL  60004
   USA

   Phone: +1-847-632-3028
   EMail: qxie1@email.mot.com


   Maureen Stillman
   Nokia
   127 W. State Street
   Ithaca, NY  14850
   USA

   Phone: +1-607-273-0724
   EMail: maureen.stillman@nokia.com



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   Michael Tuexen

   Germany

   Phone:
   EMail: tuexen@fh-muenster.de













































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Intellectual Property Statement

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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































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